The practice of cartography, or mapmaking, exists for a long time. Although a computer makes the process easier and offers the ability to explore and edit designs, as a cartographer you must still understand the basic principles behind portraying spatial data and the aesthetic challenges in designing an effective and attractive way to communicate ideas. Map designers may choose a variety of strategies for symbolizing features in a map. A data layer may simply be portrayed using one symbol, or different features can be assigned different symbols depending on the value of an attribute field. Point data are shown using...